1. Field of the Invention
The present invention relates to an X-ray generator for generating X-rays from an anticathode by causing electrons generated from a cathode to impinge upon the anticathode.
2. Description of the Related Art
The above-mentioned X-ray generator is a device for generating X-rays which are irradiated to a sample to be analyzed in an X-ray diffraction device, for example. For example, in the X-ray generator disclosed in Patent Citation 1, electrons released from a cathode body structure (corresponding to a cathode) are caused to impinge upon a tapered lateral surface of an anode target (corresponding to an anticathode) to form an X-ray focal point, and X-rays are released from the X-ray focal point. In this X-ray generator, positive ions are released from the anode target when electrons impinge upon the anode target, and there is a risk that impingement of the positive ions on the cathode may adversely affect the service life of the cathode. Impingement of positive ions on the cathode is sometimes referred to as ion bombardment.
According to Patent Citation 2, a technique is known in which a filament (corresponding to the cathode) is disposed eccentrically with respect to a Wehnelt electrode, whereby the electron irradiation region on a target (corresponding to the anticathode) is made eccentric, and positive ions released from the electron irradiation region are thereby prevented from impinging upon the filament.